Stress in a Hex socket
Stress in a Hex socket
(OP)
Hello everyone. Since I found this site I have been getting lots of great information and entertainment-thanks! I can't find the info I need so I get to make my first post. I am designing a custom fasterner with a hex socket for tightening. Are there formulas for designing hex sockets. I need to find the optimal hex depth vs width across the flats to prevent damage from the hex key torque.
thanks for the help.
JMT
thanks for the help.
JMT





RE: Stress in a Hex socket
Ted
RE: Stress in a Hex socket
If you can manufacture your custom fastener from an existing standard fastener then you will already have the original head.
The standard heads and bolts are designed for the tightening torque that the bolt can hold in order to develop a specified axial force in the bolt. A machined head bolt with the same dimensions as the standard bolt will not be able to tolerate the same torque and load.
RE: Stress in a Hex socket
design the socket to fit onto the head very closely !
it sounds like you're trying to minimise the head height. a "dumb" approach would be to machine down some bolt heads and see what works. if you want to "design" something, maybe FEA would help. I'm sure that the standard bolt head is not minimum height, but perhaps a good design proven by experience. You're thinking about the tightening torque; what about the applied loads (like tension) ?
RE: Stress in a Hex socket
Making the part thicker would require changing other parts. I want to avoid that can of worms.
Anyway, the part is completely machined from 316 stainless and the hex formed by rotary broach.
JMT
RE: Stress in a Hex socket
RE: Stress in a Hex socket
If you don't have the handbook, just tell me what size wrench you are designing for and I can give you the tolerance.
Don
Kansas City
RE: Stress in a Hex socket
Here are two types of low head fasteners that are off the shelf. These are metric but they are available in inch series. There is some torque limitations on this type head.
There is also a recessed socket flat head available.
You can buy or as stated above copy.
http://www
http:/
ket_cap_screw.html
RE: Stress in a Hex socket
Don't forget to consider the wrench end round off when you look at alternate socket depths.
Ted
RE: Stress in a Hex socket
TTFN
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RE: Stress in a Hex socket
Don - My Machinery's Handbook (24th ed) left the depth standards out. Guess I need to get an older version.
Anyway, I had not thought about looking at button heads for an example. So, I copied one and I'm having the shop make samples for testing.
JMT
RE: Stress in a Hex socket
I remember my chief stress engineer doing similar for a square drive, but can't remember details, sorry.
KENAT, probably the least qualified checker you'll ever meet...